Tuning fork gyrometers have a tendency of imposing themselves for the determination of the angular speed of a moving object, due to their small dimensions and their low costs. Complex and expensive gyroscopes have been used for a long time, in particular in aeroplanes or missiles, where they are used to follow the orientation of the aeroplane or the missile with respect to a fixed reference.
But, with possibilities of miniaturisation connected to the tuning fork gyroscope, new applications are contemplated, in particular in the field of automobiles, where they may be integrated into anti-skidding devices or devices for equilibrium correction.
An angular speed measuring device using a quartz tuning fork has been described in detail in the patent EP-B-0 515 981, of the same applicant. In a quartz tuning fork gyrometer, the arms of the tuning fork are provided with electrodes for applying an excitation signal, and with electrodes for detecting a detection signal which corresponds to the response of the tuning fork during its rotation around its longitudinal axis.
Certain documents of the state of the art, in particular the document EP 0 494 588, assume that the correct operation of a tuning fork gyrometer depends, on the one hand, on the implementation of the excitation and the detection electrodes on the tuning fork, allowing to minimise the coupling between the excitation signal and the detection signal, and on the other hand, on the quality of the electronic processing means associated to the tuning fork so as to fully exploit the useful component, typically very small, due to the Coriolis force during the movement of the gyrometer.
However, known tuning fork gyrometers are, in the present state of the art, penalised by the difficulty to measure the useful part of the detected signal corresponding to the Coriolis force, this being all the more true when the rotational speed of the gyrometer is low. Furthermore, certain components or analog devices used in the assembly for measuring the useful component of the detection signal, introduce into this component a factor depending on the effect of the temperature. Due to this fact, they render the useful component of the detection signal dependent on the temperature, while for an optimal measurement, the useful component should depend only on the angular speed.